1. Field of the Invention
This invention relates to a coaxial opto-electronic device. In particular, the present invention relates to a package structure. For example, the present invention may find particular use in opto-electronic device used in SFF (Small Form Factor) and SFP (Small Form Factor pluggable) opto-electronic transceiver module which is used to interface a host device with an optical communications network.
2. Description of the Related Art
Fiber optics is increasingly used for transmitting voice and data signals. The use of light as a transmission medium presents a number of implementation challenges. In particular, the data carried by light signal must be converted to an electrical format when received by a device. Conversely, when data is transmitted to optical network, it must be converted from an electronic signal to a light signal. A number of protocols such as ANSI Fiber Channel protocol are typically implemented to define the conversion of electronic signals to optical signals and transmission of those optical.
Typically, a transceiver module is electrically interfaced with a host device, such as a host computer, switching hub, network router, switch box, computer I/O and the like via a compatible connection port. Moreover, in some application it is desirable to miniaturize the physical size of the transceiver module to increase the port density and therefore accommodate a higher number of network connections within a given physical space. In addition, in many applications, it is desirable for the module to be inserted and removed from the host system without removing electrical power. To accomplish many of these objectives, international and industry standards have been adopted to define the physical size and shape of optical transceiver modules to ensure compatibility between the optical transceiver modules from different manufacturers. For example, in 1998, a group of optical manufacturers developed a set of standards for optical transceiver modules called the Small Form-Factor Pluggable (“SFP”) Transceiver Multi-Source Agreement (“MSA”). This standard defines the details of the electrical interface, the physical size and shape for the SFP transceiver modules and the corresponding host port, so as to ensure interoperability between different manufacturers' products.
While such standards may recommend a limited physical size, the inner opto-electronic devices also demonstrate a smaller physical size. At the same time, the standards require the chassis grounds and external electromagnetic interference shields should not be attached to circuit ground. With the trend of the metallized SFP case, the demand of the case ground of the device in SFP case insulated from the circuit ground has arisen. If the case of the device is insulated from the signal ground, it doesn't matter whether the SFP case is metal or not.
For coaxial devices applied to SFP, the problem to assure as large as possible inner space with insulating structure package has emerged.